The next wave of mobile computing is broadly associated with wearable computers, such as smart wristbands, smart watches and glasses, and other head-mounted cameras and displays, intelligent and adaptable clothing, wearable medical devices, etc. In 2015, shipments of wearable devices have exceeded 79M units. The current market of wearable devices is dominated by smart watches and smart bands (wrist band, arm band, head band activity trackers). According to market forecasts, about 110 million wearable devices will be shipped in 2016, and by 2020, annual shipments will exceed 237 million units. Wrist-worn devices, such as wristbands for activity tracking and medical purpose and smart watches, are expected to retain a high share of the early wearables market. Some analysts project a market share of wrist-worn wearables to reach 87% of all wearable shipments in 2018.
An important feature of many wearable computers is their increased ability to sense, measure and direct a physical and/or emotional condition of a user and pace of user activities. According to commonly accepted terminology, multiple wearable devices of an individual form a Body Area Network (BAN, also known as a wireless body area network WBAN or a body sensor network BSN). Devices in such network may be surface-mounted on the body in a fixed position, may be accompanied by devices which users may carry in different positions, in pockets of their clothes, by hand or in various bags; future wearable devices may even be embedded inside the body as implants. In many forecasts, an early phase of BANs is characterized by smartphone centric networks; wearable devices at this phase may be perceived as smartphone companions, communicating with other networks via a smartphone gateway, while intra-network communications between multiple wearable devices may be served by short-range wireless technologies, such as Bluetooth and NFC (Near Field Communication).
A significant portion of existing and forecasted wearable devices is designed for permanent contact with the human skin; therefore, significant research, development and commercial efforts are directed towards enhancing and optimizing device interaction with the skin. These efforts resulted in several well-received mass-market products and give rise to emerging trends:                Fingerprint scanners are a well-developed commercial market.        A new area of experimental and commercial research deals with skin conductivity for signal transmission, resulting in intra-body communications, amplifying data transmission within BANs and opening a new approach in inter-connecting various conventional devices, such as a music player and a headset.        New stretchable, flexible and visually customizable touch sensors offer an opportunity of a skin-worn touch sensitive interface in the form of touch input stickers for controlling various wearable and mobile devices, attached to the skin with a biocompatible adhesive.        For visually impaired people, touch has long been a conduit for data acquisition and communications, for example, Braille alphabet, Braille reading and books, as well as Braille printers and evolving Braille displays. There is also significant development in creating an artificial skin for prosthetic purposes.        
Notwithstanding significant progress and promising new developments in utilizing skin surface and its physical and physiological properties in the context of wearable devices and personal body networks, various application areas still remain disconnected.
Accordingly, it is desirable to design a new system, methods, devices, and user interfaces for haptic communications.